The goal of this application for renewal of training support is to develop exceptional Pre and Post doctoral investigators schooled in the fundamentals of Virology. This will be achieved in the context of modern molecular biology, viral pathogenesis, immunology and structural biology in an environment that is well known for its legacy in vaccine development. We have established a strong Pre- and postdoctoral training program whose faculty has been assembled from the University of Pennsylvania, The Wistar Institute, and CHOP community. The trainers on this program are a closely knit group of 23 of the best (out of approximately 30) active research investigators in Virology who interact with the trainees and with each other. The program is a combination of previously separate Pre and Post Doc training grants using the facilities of the University of Pennsylvania (Medical, Dental, and Vet Schools), the Wistar Institute, and CHOP. Trainees are recruited through advertisements in Nature, Science, ASM News, or through letters to chairmen of Microbiology Departments in Medical Schools and direct application to mentors. More recently the internet is increasingly being used. Ethics training and minority recruitment at Wistar is coordinated with the biomedical graduate studies office of U. Penn. There are two minority trainers in this program. The program is unique in the breadth and depth of researchers in Virology (and associated disciplines) that it offers to trainees. Many viruses are under study including DNA tumor viruses, animal and human herpes viruses, retroviruses (including HIV), rhabdo and corona viruses. The disciplines involved in these studies include molecular biology, structural biology and immunology. Each trainer has independent funding and all have active research programs. Training is supplemented by seminars featuring invited virologists, symposia, as well as weekly research seminars within the individual laboratories. The training grant organizes a highly popular weekly seminar at which the trainees in each investigators laboratory present their work and the training grant camaraderie is established and maintained.